Most DHPP vaccines in America contain an adenovirus-2 antigen for superior protection against hepatitis. The more appropriate name for this vaccine, then, should be Da2PP, but it’s still frequently called DHPP. The “H” basically equals “a2.”

(For science nerds: Hepatitis is actually caused by canine adenovirus type 1, CAV-1. But using CAV-1 in vaccines causes side effects. So CAV-2 is used in vaccines because it’s safer. CAV-2 is one of the causes of canine cough, but it also safely protects against the more serious adenovirus that causes hepatitis. Stipulating on the vaccine label that it is Da2PP means you’re getting the safe adenovirus vaccination.)

Infectious canine hepatitis can cause mild signs, like fever and anorexia, as well as serious illness and death. Again, very young dogs are most susceptible, and the disease is made worse if the dog has concurrent distemper or parvovirus infections.

Dogs with clinical ICH show high fever followed by anorexia, thirst and conjunctivitis. More serious cases cause abdominal pain, vomiting, blood clotting abnormalities and liver damage.

The L in DHLPP stands for leptospirosis, a bacteria transmitted to dogs (and people) through an infected animal’s urine. Infected standing water or bodies of water serve as a reservoir for the disease.

Infected dogs, rodents, farm animals and other wild animals can spread the disease, making this a problem in both cities and rural areas.

Leptospirosis causes liver and kidney damage. It can be treated but must be caught early in the disease process for the best prognosis. Unfortunately, the early symptoms can be vague, so treatment is often too late.

Leptospirosis may not be included in a dog’s basic vaccine protocol for several important reasons:

There is a higher potential for vaccine reactions when leptospirosis is given in a combination vaccine (DHLPP). Many vets think it should be given separately.

Vaccinating against leptospirosis is not necessarily needed in areas where the disease is extremely rare or if the dog has a sheltered lifestyle.

The leptospirosis vaccine gives a short duration of immunity (less than 1 year). Since your dog receives the DHLPP or DHPP every 3 years or less, if lepto coverage is really important in an endemic area, it should be given at least once a year.

The first P in DHLPP stands for parainfluenza virus, a less serious (but highly contagious) viral disease of dogs.

It causes respiratory signs and is generally not deadly. According to Merck Animal Health, “The virus spreads rapidly in kennels or shelters where large numbers of dogs are kept together.”

Parainfluenza is not considered a core vaccine, but it is in the majority of the classic canine vaccines. Should it be included in the vaccine? That’s up for debate.

The second P in DHLPP stands for parvovirus, a devastating viral disease in dogs.

Discovered in the 1960s, this disease caused many dog deaths until a vaccine was formulated.

Parvo affects the GI tract, causing severe vomiting, diarrhea and dehydration. Puppies are affected most and require intense supportive veterinary care if they have any chance of survival.

Before a vaccine was concocted to protect against it, parvovirus caused many dog deaths in the United States. Photo: jaminriverside

DHLPP Vaccine Schedule

Which dog vaccines are absolutely necessary?

The DHLPP or DHPP is the only canine vaccine considered essential for all dogs in the United States. That’s why it’s designated a “core” vaccine. Rabies is legally required.

The rest of the canine vaccines — like corona, Lyme disease and leptospirosis, to name a few — are considered nonessential and should be given to dogs only when a complete risk assessment about the dog’s lifestyle has been made.

The American Animal Hospital Association (AAHA) publishes vaccine guidelines every few years and updates those recommendations regularly. Veterinary immunologists and researchers devise these recommendations and protocols based on scientific data to best protect the general population of dogs.

The standard guidelines suggest the following for the DHPP vaccine:

Begin vaccinating puppies at 6–8 weeks of age.

Administer sequential doses at an interval of 2–4 weeks until at least 16 weeks of age.

Why do puppies need a series of vaccinations? Most pups receive protection known as antibodies from their moms, so they are born protected against distemper, parvo, etc. These maternal antibodies, however, start to lessen and disappear sometime between 8 and 16 weeks.

So the puppy receives multiple vaccinations during this time to make sure the vaccine begins to give them protection as the maternal antibodies wane. By 16 weeks of age, the puppy has a reasonably mature immune system, and the vaccine gives them protection for the next year.

If dogs receive their first vaccine at around 16 weeks, we recommend boosting it in 2–4 weeks to ensure protection.

Then the DHPP should be boosted again 1 year after the puppy vaccines. Administer subsequent vaccines every 3 years or less frequently. The DHPP vaccine is probably protective in most cases for longer than 3 years.

Antibody Testing

Many people are concerned about over-vaccinating.

After a dog has received several DHPP or DHLPP vaccines, a blood test — commonly called a titer — can be performed to measure the levels of distemper, parvo and adenovirus antibodies.

Measuring an antibody level may not directly correlate to protection if the dog is exposed to the virus. A positive antibody titer does not mean your dog is completely protected.

What Does the DHPP or DHLPP Vaccine Cost?

The cost is highly variable based on the individual hospital and the locality.

It is widely published that the DHPP or DHLPP vaccine should cost about $20, but I think that’s on the low side. I’ve seen city practices charge triple that. Some practices bundle vaccinations or provide “wellness” plans, so the price of a single DHLPP vaccine is not clear.

Vaccinations given at clinics in pet stores may be more reasonably priced, but these places often up-sell unsuspecting pet lovers and might give unnecessary vaccinations — costing you more money in the long run.

Remember, you’re not getting an exam at these clinics or forging a relationship with a veterinarian who you can call in case of an emergency or when you need medical advice over the phone.

The series of puppy vaccinations are more expensive, since we’re talking about giving 2–3 vaccinations over a few months. Some vets provide “puppy packages” that bundle vaccinations and services, such as stool checks, into a lump sum.

Distemper and parvo are rare these days because most dogs are vaccinated, reducing potential virus reservoirs. Photo: sterou70

Vaccine Controversies

Vaccines, vaccine schedules, and which and how many vaccines to administer to pets are highly controversial.

People hold strong opinions about vaccines and often defend their stance vehemently. Most vets listen to the concerns of clients and tailor a besoke vaccine plan for every individual pet.

While it’s true that we over-vaccinated our pets in the past — before we knew better — danger can result from the pendulum of public opinion swinging too far to the other extreme, where too many dogs go unvaccinated and diseases that were under control begin to reemerge.

There is an altruistic side to vaccinating your pets.

Why do we rarely see cases of distemper and parvo? It’s because the majority of dogs are vaccinated, and that not only gives them protection but also lessens the reservoir of the virus in the environment.

So the occasional stray or unvaccinated dog who would have been highly susceptible to distemper or parvo 40–50 years ago has much less chance of contracting those diseases today.

In shelter situations or areas where the stray population is large, outbreaks of these deadly viral diseases still occur.

“The fewer animals that are getting the vaccine, the greater the likelihood that you’re going to have a firestorm if something that is that highly communicable comes along,” says Dr. Chris Brockett, DVM, owner of Saratoga Veterinary Hospital in Wilton, New York, and president of the state’s Veterinary Medical Society.

In this video, Dr. Clayton Greenway, DVM, explains more about the “contentious” nature of vaccines for pets:

Personalize Your Pet’s Vaccinations

When tailoring a vaccination program for your individual animal — specifically as it concerns how often to boost the DHLPP vaccine — consider the following questions.

Does your dog:

Have close contact with many different dogs?

Meet and play with other dogs?

Stay in a boarding kennel?

Go to doggy daycare?

Go to a grooming facility?

Participate in dog shows or agility?

Have exposure to a shelter environment?

Visit dog parks?

Run free or hunt?

In addition to the above checklist, your vet will consider the age, health status, lifestyle and previous vaccine history of your dog.

Take, for example, Lady Gaga, a 10-year-old Toy Poodle living in a suburban neighborhood who is rarely off-leash. Gaga has been given a DHPP vaccine every 3 years for the past 10 years.

Does she still need a booster every 3 years until she’s 16? Probably not.

Now let’s walk down the road and find Homer, the 9-year-old coonhound. Whoops! We can’t find Homer because he broke through his fence again and will be gone for several hours, as he often does. When he comes home, his human will reward him by taking him to the dog park.

Should Homer continue to get a 3-year DHPP booster? Yes, I think so.

Final Thoughts on the DHPP or DHLPP Vaccine

Thanks to all of you for taking time to think about vaccination and vaccinating appropriately.